U.S. Pat. No. 4,213,624 issued Jul. 22, 1980 for Pallet Transport system discloses a dolly whose elevation above floor level may be changed by changing the level of the dolly wheels relative to the dolly frame. Such an arrangement is both time consuming and somewhat tedious because the individually adjustable wheels must be uniformly adjusted in relation to the dolly frame in order to insure that one or more of the dolly wheels is not disposed at a level different from the level of the remaining dolly wheels.